圣诞节来了，用Python Turtle画棵圣诞树吧

如何实现上图效果呢？让我们开始吧！

首先，导入turtle和random

from turtle import *
import random as rd

然后，写一个待会儿要用到的函数，用于随机生成True和False

def true_or_false(percent=50):
    n=rd.randint(1,100)
    if n<=percent:
        return True
    else:
        return False

然后初始化一下，设置颜色模式为255（RGB模式），设置画布，初始位置，绘图速度等

# initial
colormode(255)
screensize(600,600,"darkblue")
seth(90)
pu()
bk(180)
speed(0)
tracer(2)

一些常量

# constants
BROWN=160,82,45
TRUNK_LENGTH=350
TRUNK_PENSIZE=15
DECORATE_BALL_PENSIZE=4
DECORATE_COLORS=[
    (200,0,0),
    (220,220,0),
    (255,97,3)
]

树干

# trunk
pu()
seth(90)
xx=0
goto(xx,-180)
pd()
pensize(TRUNK_PENSIZE)
pencolor(BROWN)
fd(TRUNK_LENGTH)
bk(TRUNK_LENGTH)

两边的叶子，左边的叶子朝向右边（随机度数），右边的叶子朝向左边（随机度数），这段代码不难理解

# leaf
pu()
x,y=pos()

for n in range(18): # left
    seth(90)
    if n==0:
        fd(100)
    else:
        fd(20)
    seth(180)
    length=200-n*10
    fd(length)
    seth(0)
    for i in range(length):
        fd(1)
        if i%6==0:
            pd()
            seth(rd.randint(45,75))
            pencolor((0,rd.randint(110,180),0) if true_or_false(80) else (255,255,255))
            pensize(10)
            fd(30)
            bk(30)
            seth(0)
            pu()

pu()
goto(x,y)
for n in range(19): # right
    seth(90)
    if n==0:
        fd(100)
    else:
        fd(20)
    seth(0)
    length=200-n*10
    fd(length)
    seth(280)
    for i in range(length):
        fd(1)
        if i%6==0:
            pd()
            seth(rd.randint(105,135))
            pencolor((0,rd.randint(110,180),0) if true_or_false(80) else (255,255,255))
            pensize(10)
            fd(30)
            bk(30)
            seth(180)
            pu()

伯利恒之星，一开始画位置不太对，经过多次调整后确定为如下代码

# star
pu()
goto(xx,pos()[1])
seth(180)
fd(20) # micro moving
seth(90)
fd(20) # micro moving

pd()
color((255,0,0))
seth(72)
begin_fill()
for i in range(5):
    fd(80)
    right(180-180/5)
end_fill()

一些装饰

# ball (decorate)
positions=[(-159,-55),(-91,14),(-83,-36),(85,-54),(-22,-40),(-3,34),(0,160),(-47,152),(19,215),(115,22),(68,107),(141,-48)]
pensize(DECORATE_BALL_PENSIZE)
for x,y in positions:
    pu()
    goto(x,y)
    r=rd.randint(12,22)
    seth(90)
    fd(r)
    seth(0)
    fillcolor(rd.choice(DECORATE_COLORS))
    pencolor(rd.choice(DECORATE_COLORS))
    pd()
    begin_fill()
    circle(r)
    end_fill()

DONE！！

done()

好啦，看一看全部代码吧！

from turtle import *
import random as rd

def true_or_false(percent=50):
    n=rd.randint(1,100)
    if n<=percent:
        return True
    else:
        return False

# initial
colormode(255)
screensize(600,600,"darkblue")
seth(90)
pu()
bk(180)
speed(0)
tracer(2)

# constants
BROWN=160,82,45
TRUNK_LENGTH=350
TRUNK_PENSIZE=15
DECORATE_BALL_PENSIZE=4
DECORATE_COLORS=[
    (200,0,0),
    (220,220,0),
    (255,97,3)
]

# trunk
pu()
seth(90)
xx=0
goto(xx,-180)
pd()
pensize(TRUNK_PENSIZE)
pencolor(BROWN)
fd(TRUNK_LENGTH)
bk(TRUNK_LENGTH)

# leaf
pu()
x,y=pos()

for n in range(18): # left
    seth(90)
    if n==0:
        fd(100)
    else:
        fd(20)
    seth(180)
    length=200-n*10
    fd(length)
    seth(0)
    for i in range(length):
        fd(1)
        if i%6==0:
            pd()
            seth(rd.randint(45,75))
            pencolor((0,rd.randint(110,180),0) if true_or_false(80) else (255,255,255))
            pensize(10)
            fd(30)
            bk(30)
            seth(0)
            pu()

pu()
goto(x,y)
for n in range(19): # right
    seth(90)
    if n==0:
        fd(100)
    else:
        fd(20)
    seth(0)
    length=200-n*10
    fd(length)
    seth(280)
    for i in range(length):
        fd(1)
        if i%6==0:
            pd()
            seth(rd.randint(105,135))
            pencolor((0,rd.randint(110,180),0) if true_or_false(80) else (255,255,255))
            pensize(10)
            fd(30)
            bk(30)
            seth(180)
            pu()

# star
pu()
goto(xx,pos()[1])
seth(180)
fd(20) # micro moving
seth(90)
fd(20) # micro moving

pd()
color((255,0,0))
seth(72)
begin_fill()
for i in range(5):
    fd(80)
    right(180-180/5)
end_fill()

# ball (decorate)
positions=[(-159,-55),(-91,14),(-83,-36),(85,-54),(-22,-40),(-3,34),(0,160),(-47,152),(19,215),(115,22),(68,107),(141,-48)]
pensize(DECORATE_BALL_PENSIZE)
for x,y in positions:
    pu()
    goto(x,y)
    r=rd.randint(12,22)
    seth(90)
    fd(r)
    seth(0)
    fillcolor(rd.choice(DECORATE_COLORS))
    pencolor(rd.choice(DECORATE_COLORS))
    pd()
    begin_fill()
    circle(r)
    end_fill()

done()

里面的参数可以自己修改，喜欢的话就来个3连吧~~~